A knee brace can be worn by a post-operative patient who has had knee surgery. Knee braces also can be worn by persons who suffer knee instabilities or other persons engaged in sports activities to prevent injuries to the knee. The common purpose of a knee brace is to provide exterior support for the knee to prevent any unnatural movements of the knee joint which could injure or reinjure the knee ligaments, while allowing the normal swinging movement of the knee joint about a horizontal axis through the knee (viz., forward and backward movement of the lower leg or tibia relative to the upper leg or femur, as in a normal walking motion). One type of motion to be prevented by a knee brace is a sudden movement of the upper and lower legs to one side or the other. Another type of motion to be resisted is a twisting or rotation of either the upper leg or the lower leg relative to the other about a vertical axis.
Several knee braces used for post-operative patients have been developed in recent years. These prior art knee braces include the braces disclosed in U.S. Pat. No. 3,669,105 to Castiglia and U.S. Pat. No. 4,372,298 to Lerman. Both of these braces are primarily considered to be post-operative braces intended to be fitted by an orthosist who carefully shapes the brace to the patient's lg. In fact, the Castiglia brace is custom fitted to a plaster cast of the patient's leg. Both braces are therefore accurately fitted by a skilled professional for providing rigid contact with both sides of the knee through the full range of knee motion. The required support throughout the full range of motion at the knee is needed to protect the knee joint during the post-operative rehabilitation period.
Separate and apart from post-operative knee braces, there is also a need for a lighter weight, less expensive and more comfortable brace that can be worn as an interim brace after an initial post-operative rehabilitation period, in order to continue providing protection for the knee joint as it heals.
There is also a need for a lighter weight more comfortable and less expensive preventive knee brace, one that can be worn during sports activities to prevent injuries to the knee. Similar knee braces also are needed for preventing injuries or undue stress on the knee joint for those persons who have weak knee joints possibly caused by arthritis, congenital defects, a sprained knee joint, or possibly less severe strains to the ligaments of the knee.
Sports injuries are a common cause of injuries to the knee ligaments, especially sports such as football and basketball. Players who play football at the college and professional levels are especially susceptible to knee injuries when playing on artificial turf. In recent years some football and basketball players who have had knee surgery have worn knee braces in games to allow the players to resume play earlier and to protect their knees from further injury. Such knee braces are usually rather large and bulky, and they restrict the athlete's performance to some extent. It would be desirable to provide a prophylactic knee brace that can be worn by such athletes in games and in practice to prevent injuries from occurring in the first place. The need for such a preventive knee brace extends to persons with knee problems who are engaged in a wide variety of recreational sports. The present invention provides a preventive knee brace which is light in weight and does not restrict the normal motion of the knee joint, so the athlete can perform at his or her best even though wearing the brace. Moreover, the knee brace is able to absorb the impact of a blow from different directions, while preventing undue sideways motion of the knee, twisting of the knee, or forward or rearward sliding movement of either the upper leg or the lower leg relative to the other.
One prior art knee brace that has been used for preventing sports injuries is the knee stabilizer disclosed in U.S. Pat. No. 4,249,524 to Anderson. The knee stabilizer disclosed in that patent has metal uprights for extending along the sides of the upper and lower legs, and a single metal support bar that pivots freely to each of the uprights. The brace protects against undue sideways motion of the knee joint from an impact to the side of the knee, as well as protecting against twisting of the knee. However, inasmuch as both ends of the support bar pivot freely to the upper and lower uprights, this free pivoting motion cannot prevent undue sliding motion of the upper leg relative to the lower leg, or vice versa, from impacts coming from the front or rear of the leg. The knee joint of a football player is especially susceptible to blows from the front of the knee, but the knee stabilizer disclosed in the Anderson patent cannot prevent undue stress on the knee ligaments in those situations.
One embodiment of this invention provides a preventive knee brace that is especially useful for athletes to wear in practice or in a game, without causing an undue restriction of the normal motion of the knee. The brace is light in weight and protects against the common causes of knee injuries by preventing undue stress on the knee joint from impacts at the side of the knee, or from the front or rear of the knee, as well as protecting against undue twisting of the knee joint. The knee brace is especially useful in preventing hyperextension of the knee from an impact at the front of the knee, as well as protecting against forward or rearward sliding movement of the upper leg relative to the lower leg, or vice versa. It should be emphasized that lateral impact stresses on the knee joint are best prevented by the knee support. A front impact that can result in hyperextension of the knee joint is prevented second bests. A rear impact stress or stresses due to rotation are prevented third best. The brace does not eliminate all front impact stresses, but it does provide stability sufficient to offer a level of protection against hyperextension injuries. The Anderson stabilizer, on the other hand, does not provide the same level or hyperextension protection because of its freely rotatable nature under a front impact.